ES2724224T3 - Layer deposition procedure on a glass substrate by low pressure PECVD - Google Patents

Abstract

Production process of oxide, nitride or metal oxynitride or semi-conductive films on a substrate, by means of the PECVD method, which comprises the steps that consist of: a) providing a low pressure PECVD device, which It comprises at least one plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, for depositing said films on the substrate, b) applying an electric power between the two electrons of such so that the power density of the plasma is between 5 and 50 W per cm2 of plasma, and, c) applying a gaseous precursor of oxides, nitrides or metal oxynitrides or semi-conductive films on the substrate at a flow rate between 100 and 500 sccm per linear meter of the plasma source, and a reactive gas based on oxygen or oxygenated derivatives or nitrogen derivatives at a flow rate between 500 and 20,000 sccm per me linear tro of the plasma source.

Description

DESCRIPTION

Layer deposition procedure on a glass substrate by low pressure PECVD

The present invention relates to a process of depositing layers on a glass substrate by low pressure PECVD using organometallic type precursors.

The deposition of layers, such as SiO2 and TiO2, by means of the sputtering technique, especially magnetron spraying, has the advantage of allowing to obtain thin layers of compounds in the form, for example, of polycrystals. This advantage makes this technique very widespread in the field of glass and also presents compatibility with microelectronics procedures.

Recent studies have shown that the PECVD technique ("Plasma Enhanced Chemical Vapor Deposition") has increasing benefits in the industrial world, especially glass.

The PECVD comes from the CVD (chemical vapor vapor deposit). The CVD consists of sending, in a hot substrate, chemical reagents or precursors, previously vaporized and which are decomposed by pyrolysis on contact with the hot substrate. This procedure is usually applied "online" during the production of float glass. Thin layers are thus obtained (of the order of some nanometers up to hundreds of nm), especially of oxides. The layers obtained are dense, of high purity and generally very chemically stable, as well as mechanically. Deposit rates are high.

However, the range of materials that can be deposited by CVD is limited, since it is difficult to find volatilizable precursors and they will pyrolize in the temperature range accessible to glass manufacturers (500-750 ° C). A possibility to get rid of the substrate temperature and, therefore, expand the range of precursors usable in CVD and, therefore, the range of materials that can be deposited, combine the classic CVD, possibly at a lower temperature, with a plasma device

The PECVD can be carried out with the help of any plasma: cold plasmas (without equilibrium) or thermal plasmas (with equilibrium). Cold plasmas are generally preferred. Active plasma species, such as electrons, ions, radicals, typically have several electron volt (eV) energies and can thus cause dissociation or activation of chemical precursors. To keep the plasma out of balance, it is often necessary to work under reduced pressure. Most known PECVD techniques therefore use low pressure plasmas.

Plasma can be generated through sources that use known and commercially available devices. Plasma sources should preferably guarantee the use in a wide pressure range and in a panel as wide as possible of substrates to be coated, produce a dense beam of high performance, avoid fouling of the source and the use of electron sources to filament base Mention may be made of the PBS sources (Plasma Beam Source), the PDP sources (Penning Discharge Plasma) and the microwave sources. Within the PBS sources, one can cite the hollow cathode plasma sources (see eg WO2010 / 017185) and the linear double-beam sources (Dual Beam pBstm) which comes especially from GPi (General Plasma Inc. ) (see, for example, H. Chandra et al., GPi, "Recent Development of Low Temperature PECVD of Transparent Conducting Oxide in photovoltaic applications", p.1-4, available online at www.generalplasma.com ; J. Madocks et al., Material Science and Engineering B 119, (2005), 268-273; J. Madocks et al., LCCG8-Braunschweig 2010 - proceedings, 139-143; US 2006/0177599 A1).

With regard to magnetron spraying, the PECVD gives access to plasmas that have lower temperatures, which allows the deposit of more numerous different materials. In addition, the films have sufficient adhesion on the substrate to allow post-deposition treatments, such as tempering or rolling, and can be obtained with greater thicknesses.

As mentioned above, PECVD technology has the advantage, especially, of allowing deposits of different layers, transparent, semi-transparent or non-transparent, based on oxides, nitrides, oxynitrides, metal oxycarbons or semi-conductors, such such as SiO2, TiO2, SnO2, ZrO2, A ^ Oa, in, for example, photovoltaic, solar control or display applications. However, the desired physical, optical and electrical properties of such layers depend on parameters, such as the nature of the precursors used, the gas flow rate according to the reactive gas / precursor molar ratio, the nature of the reactive gases, the pressures of use and plasma sources, as mentioned above.

As an example, SnO2: F layers have been produced by PECVD using as a source the “Dual PBSTM”, on substrates several meters wide, in line, at a temperature T ° C lower than 130 ° C, with deposit rates of 200-300 nm.m, / min and a film uniformity better than 3%, that is to say that the variation in thickness of the film considered over the entire width of the glass varies only a maximum of 3%. These SnO2: F films have a "bulk" resistivity of 2.18.10-3 Ohm.cm at 130 ° C, lower than usual value obtained with other PECVD methods at the same temperature, excellent electrical properties, due to a residual percentage of carbon less than 1%, and optical for a low value of the coefficient £ (molar extinction coefficient), less than 0.01 between 400 and 1100 nm (H. Chandra et al., Cited above).

The article by J. Madocks et al. (ICCG8- Braunschweig 2010 - proceedings, 139-143) describes a PECVD installation and the conditions for depositing SiO2 barrier layers and their properties. It is shown that the SiO2 layers obtained by this method have much better barrier properties to the migration of sodium ions than SiO2 layers manufactured by magnetron spray. The embodiment described here is also more efficient since it allows working with faster deposit speeds (> 150 nm.m / min), at a temperature below 50 ° C and which allows working online to make deposits at industrial scale In addition, this article also describes the properties of TiO2 films, especially emphasizing the increased optical qualities of these films obtained with deposit rates much more important than with the magnetron.

However, in the case of SiO2 and TiO2 layers, a proportion of pollutants, such as carbon or hydrogen, is found, which can pose problems on the properties of the film during subsequent heat treatment such as tempered glass with coating.

In the article J. Madocks et al. (Material Science and Engineering B 119, (2005), 268-273) mentioned above, the water barrier properties of the SiO2 layers on a polymer substrate (polyethylene-PET) have been measured. In this regard, the conditions of realization have shown that the water barrier properties increase when the flow of O2 (reactive gas) decreases, which means that identical water barrier properties can be obtained with a SiO2 film having a thickness three times lower, and this flow of O2 is reduced further, being, on the other hand, everything else equal. However, increases in carbon content are observed in these films with the corresponding decrease in O2 flow. This observation goes in the sense of what is already known: the more the O2 content increases, the more the carbon content in the films will decrease, that is, more O2 molecules interact with the carbon of the organic precursors.

However, the O2 flow rate alone is not sufficient to reduce the carbon content in a SiO2 film for example. Other parameters have an influence on this, such as the electrical power applied to the electrodes of a PECVD device, more specifically the plasma power density, the flow rate and the nature of SiO2 precursors, such as TMDSO (tetramethyldisiloxane) and HMDSO (hexamethyldisiloxane), of TiO2, such as ethoxytyitanium, of SnO2, such as tetramethyltin, of Al2O3, such as trimethylaluminum, with respect to the partial pressure of reactive gas, such as O2. Consequently, these parameters determine the deposit rates (nm.m / min), since in order to obtain a high deposit rate, it is necessary that the precursor gas flow is high, which leads to a low partial pressure. of reactive gas that leads to an unacceptable carbon content in the layers.

One of the objectives of the present invention is to obtain deposits of layers of oxides, nitrides or metal or semi-conductive oxynitrides, by using a low pressure PECVD process, which is typically between 0.5 and 0.001 Torr, which allows fast deposit rates and minimizes the amount of contaminants that come from the precursor.

The invention relates, in a first aspect, to a method of producing films of oxides, nitrides or oxynitrides of metals or semi-conductors on a substrate, by means of the PECVD method comprising the steps consisting of:

a) be provided with a low pressure PECVD device, comprising at least one source of double linear plasma beams, which comprises at least two electrodes connected to a pulsed AC or DC regenerator, for depositing said films on the substratum,

b) apply an electric power between the two electrodes such that the plasma power density is between 5 and 50 W per cm2 of plasma, and

c) Apply a gaseous precursor of oxides, nitrides or metal or semi-conductive oxynitrides films on the substrate at a flow rate between 100 and 1000 sccm per linear meter of the plasma source, and a reactive gas based on oxygen or oxygenated derivatives or nitrogen derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source.

Alternatively, the invention relates to a process for producing oxides, nitrides or metal or semi-conductive oxynitrides films on a substrate, by means of the PECVD method comprising the steps consisting of:

a) be provided with a low pressure PECVD device, comprising at least one hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, for depositing said films on the substrate,

b) apply an electric power to the plasma source so that the plasma power density is between 15 and 100 kW per meter of plasma, and

c) Apply a gaseous precursor of oxides, nitrides or metal or semi-conductive oxynitrides films on the substrate at a flow rate between 100 and 1000 sccm per linear meter of the plasma source, and a reactive gas based on oxygen or oxygenated derivatives or nitrogen derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source.

The applicant has shown that, by using the procedure, it was possible to obtain films of different oxides, nitrides or oxynitrides of metals or semi-conductors in which residues from the precursor are present in percentages of a maximum of 2% , even at most 0.5%, advantageously at most 0.1 atomic. The applicant has found that this is possible only by the necessary combination of the PECVD source attached to the generator of stage a), of the specific plasma power densities and when, preferably, the relationship between the reactive gas flow rate and the flow rate The gaseous precursor is at least the one necessary to obtain said films. Thanks to this low residue content, the layers of these oxides, nitrides or oxynitrides, when deposited on a glass substrate, allow to preserve, even optimize, the optical, electrical and structural properties, such as ion migration barrier sodium, control of the "beam", anti-scratches, anti-reflective, which allow to "cool" the surfaces of glass substrates, and / or ensure a homogeneous and defective tempering of the film thus deposited. The PECVD procedure has all the advantages of realization listed above: high deposit rate, typically of the order of at least 100 nm.m / min., Ease of realization on an industrial scale, excellent uniformity of the layers obtained (<5%) and moderate cost of facilities.

Within the scope of the invention, residues that come from the precursor are understood as any atom present in the starting precursor molecule and which is undesirably found in the film.

The plasma power density is defined as the power dissipated in the plasma, generated at the electrode level with reference to the plasma size.

The "linear meter of the plasma source" also referred to herein as "total plasma length" is defined as the distance between the ends of the plasma in the direction of the width of the substrate to be coated.

For a source of double linear plasma beams, the "plasma power density" can be defined as the total power applied to the source, divided by the total surface of the plasma, itself defined as the surface parallel to the substrate filled with plasma which comes from the plasma source, and calculated by multiplying the total length of the plasma by its total width. The "total plasma width" is defined as the distance between the ends of the plasma in the direction of movement of the substrate to be coated.

For a hollow cathode plasma source, the "plasma power density" can be defined as the total power applied to the source, divided by the total plasma length.

More specifically, the molar ratio of reactive gas / gaseous precursor is advantageously for films of type M (x) Ox / 2, greater than or equal to (x / 2 - y) / z, where x is the valence of metallic oxide to be obtained, being and the number of oxygen atoms present in the starting precursor and z being the number of oxygen atoms present in the reactive gas.

Also, the molar ratio of the gases, for films of type M (x) Nx / 3, is advantageously greater than or equal to (x / 3 - y) / z, where x is the valence of the metal nitride to be obtained, being and the number of nitrogen atoms in the starting precursor and where z is the number of nitrogen atoms present in the reactive gas.

Step a) of the process requires a low pressure PECVD device, which is preferably between 0.001 and 0.5 Torr, preferably between 1 and 30 mTorr and, more preferably, between 3 and 20 mTorr, provided with a source of double linear plasma beams or a hollow cathode plasma source, connected to a pulsed AC or DC generator, whose frequencies are usually between 5 and 150 kHz, preferably between 5 and 100 kHz, or to a DC generator ( the latter only in the case of a hollow cathode source).

PECVD devices with a source of double linear plasma beams that are particularly suitable for the invention are commercially available and may, for example, come from the GPi company (General Plasma Inc - USA). These are sources of double linear plasma beams attached to a pulsed AC or DC regenerator. Such sources are also commercially available under the word "Dual Beam PBSTM" (Plasma Beam Source). Alternatively, PECVD devices with hollow cathode-based plasma source (“hollow cathode ”), which is also linked to the generators mentioned above, also particularly agree with the invention.

An example of a PECVD device is described below. The PECVD source is connected in a chamber under vacuum. This chamber under vacuum is arranged in such a way that it allows obtaining the ones next to the other different sources that have different deposit modes. Typically, these sources, which allow different deposit modes, are flat or rotating cathodes for magnetron spray tanks. A specific cover has been manufactured to allow the installation of the PECVD source to a position where a magnetron spray source is usually installed. This type of vacuum chamber or “coater” is arranged to make deposits of complex layers (stacking) on large substrates, for example a glass plate 3.21 m wide and 6 meters long, moving the substrate successively below the deposit sources. As such, this vacuum chamber thus modified allows complex layer deposits that combine magnetron spray and PECVD deposits on large substrates.

The PECVD source used may consist of a source of double linear plasma beams, comprising two cavities in which the discharge takes place and openings from which it is ejected. Each cavity is connected to a conduit that allows a gas to be ionized into the cavity, and includes an electrode connected to a power generator that discharges either alternating current (AC) or pulsed DC. The electrode is capable of supporting at least one magnetron discharge in the cavity. In the plasma source is a series of magnets that face each other and border the cavity. These magnets are arranged in order to create a null magnetic field point in the cavity in which the discharge occurs. Being connected to the AC generator the electrodes of each cavity, alternatively, in each semi-cycle, are either the anode or the cathode. The gas injected into each cavity is thus ionized and forms an ion beam, forming what is called a plasma source that is emitted out of the source through an opening in the direction of the substrate.

Alternatively, the PECVD source used may consist of a hollow cathode comprising, for example, two cavities that form two electrodes connected to a pulsed AC or DC generator, in which the discharge and openings from which it is ejected takes place. Each cavity is connected to a conduit that allows a gas to be introduced into the cavity that will ionize.

The ionizable gas is generally O2 or a mixture O2 / Ar for the deposit of oxides, nitrogen (N2) or a mixture N2 / Ar for the deposit of nitrides, a mixture of N2 / O2 or N2 / O2 / Ar for the tank of oxynitrides. The frequency of the power generator is usually between 5 and 150 kHz, preferably between 5 and 100 kHz. Outside the plasma source, the condensable precursor gas is injected uniformly along the plasma source. This precursor gas is activated by this plasma. The substrate is brought near the source and a thin layer is deposited on the activated gas substrate. The amount of ionizable gas introduced into the cavity is controlled by mass flow meters that are placed on the conduit between the gas tank and the plasma source. The amount of precursor gas injected into the plasma and the ion flow rate are controlled by a liquid / vapor mass flow meter. The working pressure range for the plasma probe is usually between 1 and 500 mTorr. The pumping is preferably guaranteed by turbo-molecular pumps. In order to obtain a good uniformity of the deposit on the substrate, a pumped up through the source is preferred.

Preferably, the ratio between the reactive gas flow rate and the gas precursor flow rate is at least 5, advantageously between 5 and 30.

The temperature at which the substrate is carried is between 20 ° C and 550 ° C. The substrate is very advantageously a usual glass substrate, such as a clear, extra-clear or tinted glass, of varying thickness. It can also be metal substrates, such as steel, or polymers, such as polymers of derivatives and polyethylene. In the context of the invention, it may also be a substrate that is already previously coated by another layer, such as in the case of a stack on a substrate intended for solar control, for photovoltaic, decorative uses (for example, mirrors ), architectural and automobile. Thus, the layers according to the invention can advantageously be used as the outermost layer of a stack, or within the stack or directly on the glass in order, for example, to impart anti-reflective and anti-scratch properties to the substrate thus coated, mist or barrier layer control.

Preferably, the films of oxides, nitrides or oxynitrides of metals or semi-conductors are selected from the group consisting of SiO2, TiO2, SnO2, ZrO2, Al2O3, AlN, TiN, ZnO, silicon nitride, TaN, WO3, Cr2Ox, being x between 3 and 6, and CrN, said components being able to be doped, as well as the alloys of these components or others, which contain a maximum of atomic 2% of precursor residues, especially selected from the group consisting of H, C , Cl, derivatives of CHx, derivatives of NHX, and derivatives of OHx, with x comprised between 1 and 4. Whatever the nature of the residue, it is present in an amount of at most 2 atomic% with respect to the total number of metal atoms of the film, advantageously of a maximum of 0.5%, and very advantageously of a maximum of 0.1%. The determination of this percentage is preferably carried out by XPS photoelectron spectroscopy or by secondary ionization mass spectrometry SIMS; It can also be performed by Raman spectroscopy, by ion beam analysis techniques, such as NRA and RBS, and others.

Preferably, in step a), the source of the PECVD device has dimensions between 250 mm and 4000 mm in length and between 100 and 800 mm in width, providing a power between 5 kW per linear meter of the plasma source and 50 kW, advantageously between 10 and 35 kW per meter of the plasma source. In step b), in the case of a source of double linear plasma beams, a power density is applied between the two electrodes such that the power density is between 5 and 50 W per cm2 of plasma. Below this power density of 5 W per cm2 of plasma, an important presence of precursor residues is observed, and beyond 50 W per cm2 of plasma, the formation of dust in the gas phase that affects quality is observed of the deposit.

In step b), in the case of a hollow cathode plasma source, a power density is applied between the two electrodes such that the power density is between 15 and 100 kW per meter of plasma, preferably between 15 and 60 kW per meter of plasma. Below this power density of 15 kW per m of plasma, a significant presence of precursor residues is observed, and

The organic precursors of step c) depend on the nature of the layer to be deposited. They are volatile products, in particular at the temperatures of the process. SiO2 precursors are typically SiH4 (silane), TMDSO (tetramethyldisiloxane) and HMDSO (hexamethyldisiloxane); TiO2, ethoxy silane, TTIP (titanium tetra-isopropoxide); of SnO2, tin alkyls, such as tetramethyltin, tin chloride (SnCl4), organochlorinated tin, such as MBTC (tin monobutyl trichloride); of Al2O3, alkyl aluminum, such as trimethylaluminum; of ZnO, zinc alkyls, such as diethyl zinc; Not being this exhaustive list. Depending on the case, the precursor may further comprise a complementary precursor, for example to include a specific dopant, such as antimony or fluorine, in a layer typically of SnO2. Such complementary precursor may be SF6 for fluorine, and an organochlorine compound for antimony.

The flow rate of the gaseous precursor is between 100 and 500 sccm ("standard cubic centimeters per minute") per linear meter of the plasma source, preferably between 150 and 500 or between 200 and 500 sccm per linear meter of the plasma source. This interval is necessary to obtain the percentage of important deposits appropriate for this technique, of the order of 100 to 400 nm.m / min.

The reactive gas is based on oxygen or oxygenated derivatives, the latter being preferably selected from the group consisting of ozone, hydrogen peroxide, water, CO2 or nitrogen derivatives, preferably selected from the group consisting of N2, NH3, N2O, HCN. According to some embodiments, the reactive gas can also advantageously include an inert gas, such as helium, nitrogen, argon, neon or krypton, in order to favor the chemical dissociation of the precursors and control the ionic bombardment by the fountain. The proportion of inert gas in the total mixture (reactive gas - inert gas) is defined by the ratio between the flow rate of the reactive gas and the flow rate below 0.5 nm, which, for a strain of SiO2 with, for example, a thickness between 20 and 40 nm, can substantially improve the barrier properties.

The flow rate of the reactive gas is between 500 and 20,000 sccm per linear meter of the plasma source, preferably between 800 and 20,000 or between 1000 and 20,000 sccm per linear meter of the plasma source. Such values have the advantage of ensuring a quantity of reactive gas sufficiently higher than that of the precursors, allowing to strongly limit, even eliminate, the incorporation of C in the layer.

The layers are generally manufactured such that their geometric thickness is between 2 and 1500 nm, preferably between 20 and 800 nm, in particular between 30 and 600 nm. The thickness chosen depends on the desired technical effect for the substrates so coated.

The applications of this procedure are related to the nature of the layer deposited on the substrate. In the following, various embodiments of the invention are described, for different applications. According to a first embodiment, the process is carried out for the production of a glass substrate on which a layer of SiO2 is deposited, in direct contact with the substrate, preventing the migration of sodium ions from the crystal (layer barrier). The carbon content of this layer should be as low as possible, less than 2% atomic, even, advantageously, less than 0.1% atomic to allow the tempering of the substrate. This low percentage of carbon limits, even prevents, at the end of tempering, the appearance of defects, such as unwanted fog, cracks and CO2 bubbles trapped in the film. The layer thus obtained has a good density measured by Ra, less than 2 nm, whose thickness is between 10 and 40 nm. Usually, such a layer is used during the production of the Low-E glass substrate, advantageously in line, then a Low-E layer is deposited on the SiO2 barrier layer. The Low-E layers can be SnO2: F, SnO2: Sb, ITO (tin doped indium oxide) or other layers obtained by magnetron, such as Ag-based multilayers. The procedure is then performed with a power density greater than 5 W per cm2 of plasma for a linear double beam plasma source or greater than 15 kW per meter of plasma for a hollow cathode plasma source, the speed of tank less than 400 nm.m / min, preferably between 200 and 100 nm.m / min. The pressures are between 3 and 20 or 3 and 15 mTorr. An organic silane derivative, such as TMDSO, and pure oxygen as a reactive gas is used as a precursor, the ratio between the oxygen flow rate and the organic silane derivative flow rate being greater than 5, preferably greater than 10, even greater at 15, ie an oxygen flow of 1000 sccm for a linear source 250 mm in length, and a precursor flow of 100 sccm. The source defined in step a) of the PECVD device is preferably placed before the subsequent layer coating system, such as Low-E, which can be deposited by magnetron spray or by CVD. The above values of Ra can also be obtained by the addition of an inert gas so that the ratio between the flow of the reactive gases and the flow of the inert gas is at least 5, advantageously between 5 and 30, preferably between 5 and 20, more preferably between 5 and 15, in particular around 8. In a variant, the Ra values mentioned above can be obtained by modifying the cathode voltage, which can be done by changing the constituent material of the electrode or adapting the modules of the power generator or changing the pressure. It is usually passed from a voltage of approximately 400 V to approximately 340 V, even 300 V. In another variant, the desired Ra values can be obtained by increasing the pressure to values between 7 and 20 or between 7 and 15 mTorr, the values of 9-10 mTorr those that give the best results.

According to a second embodiment, the process is performed for the production of SiO2 layers deposited either directly on a glass substrate, or in stacking with other layers in any position, or as the outermost layer of a stack for control of mist values in stacks intended for solar applications, such as photovoltaic, which incorporates Low-E layers. The layer must necessarily contain a percentage of carbon less than 0.2%, and its thickness is typically 2 to 100 nm. Depending on the case, high mist values are necessary to favor the photovoltaic effect and improve the photoconversion performance. In other applications, for example, architectural, fog values as low as possible may be necessary. Due to the adaptation of the parameters of the process of the invention, the lowest possible mist values are required. By adapting the parameters of the process of the invention, a layer of SiO2 can be provided which confers a high mist of at least 5%, even at least 10-20%. For this purpose, the power density is a maximum of 10 W per cm2 of plasma for a linear double beam plasma source or a maximum of 20 kW per meter of plasma for a hollow cathode plasma source, the precursor flow rate gas of an organic silane derivative, such as TMDSO, is less than 400 sccm per linear meter of plasma source, preferably between 100 and 400 sccm per linear meter of plasma source, the ratio between oxygen flow rate (reactive gas) and The flow rate of the gaseous precursor is greater than 5, the deposition rate being less than 400 nm.m / min, preferably between 300 and 200 nm.m / min. For low fog, typically less than 0.5%, the power density is at least 5 W per cm2 of plasma for a linear double beam plasma source or at least 15 kW per meter of plasma for a source of hollow cathode plasma, the pressure is greater than 5 mTorr, the gas precursor flow rate of an organic silane derivative, such as TMDSO, is less than 400 sccm per linear meter of plasma source, preferably between 100 and 400 sccm per meter Linear plasma source, the ratio between the oxygen flow rate (reactive gas) and the flow rate of the gaseous precursor is greater than 15. The deposition rate is less than 400 nm.m / min, preferably between 200 and 100 nm.m / min and ideally less than 100 nm / min.

According to a third embodiment, the process is carried out for the production of layers selected from the group consisting of SiO2, ZrO2 and Al2O3, deposited either directly on a glass substrate, or as the outermost layer of a stack with the aim of confer anti-scratch properties to the coated substrate or not. The thickness of the layer, deposited directly on the glass substrate, is generally between 100 and 1500 nm, advantageously between 200 and 1000 nm, the power density being between 10 and 40 W per cm 2 of plasma for a double source linear beam of plasma or between 20 and 50 kW per meter of plasma for a hollow cathode plasma source, the pressure is less than 10 mTorr, the flow rate of gaseous precursor of an organic silane derivative, such as TMDSO, is between 150 and 500 sccm per linear meter of plasma source, the ratio between the flow rate of oxygen (reactive gas) and greater than 10. The deposition rate is less than 400 nm.m / min, preferably between 200 and 100 nm. m / min

DBT ("Dry Brush Test") anti-scratch tests performed over 4000 cycles (ASTM D 2486) show, for example, much better results than for a bare glass substrate for SiO2 layers of approximately 20 nm. When such a layer is deposited on a glass substrate previously coated with a Low-E silver-based layer, the thickness of this silica layer should preferably be greater than 40 nm, preferably greater than 60 nm, advantageously between 80 and 100 nm.

According to a fourth embodiment, the process is performed for the production of stacks on a glass substrate that has anti-reflective properties (AR). One can, for example, consider a stack comprising a succession of layers of high refractive indexes, such as TiO2, and low refractive index, such as SiO2. SiO2 is then deposited by the process of the invention, TiO2 by magnetron spray. This is possible thanks to the highly transparent properties of SiO2, whose thicknesses are classically used in this application. The absorption of light in the SiO2 film must then be less than 1%, better still less than 0.5%, even less than 0.2%. The procedural conditions to choose in this case are the following. The power density is between 10 and 40 W per cm2 of plasma for a linear double beam plasma source or between 20 and 50 kW per meter of plasma for a hollow cathode plasma source, the pressure being less than 20 mTorr, the gaseous precursor flow rate of an organic silane derivative, such as TMDSO, it is less than 400 sccm per linear meter of plasma source, preferably between 150 and 300 sccm per linear meter of plasma source, the ratio between the oxygen flow rate (reactive gas) and the flow rate of the gaseous precursor is greater than 5 and ideally greater than 15, the deposition rate being less than 400 nm.m / min, preferably between 100 nm.m / min and 200 nm.m / min, or even better below 100 nm.m / min. This guarantees a percentage of carbon in the SiO2 layer of less than 2%, even less than 0.5% or 0.1%.

For this same application (anti-reflective properties), a highly transparent layer of SiO2 can be deposited on a glass substrate which is coated with a Low-E layer, as described above. In this case, the Low-E layer is deposited, for example, by magnetron spray and, the SiO2 layer, by the process of the invention, advantageously on the same line. The reflection of the layer side is reduced by 10%, advantageously it is reduced by 20-40%, with respect to a Low-E stacking without this SiO2 layer. The procedure is then performed with a power density greater than 5 W / cm2 of plasma for a linear double beam plasma source or greater than 15 kW per meter of plasma for a hollow cathode plasma source, the gas precursor flow rate of an organic silane derivative, such as TMDSO, is less than 400 sccm per linear meter of plasma source, preferably between 100 and 300 sccm per linear meter of plasma source, the deposition rate being less than 200 nm.m / min , preferably less than 150 nm.m / min, in particular less than 100 nm.m / min, the pressure being less than 20 mTorr. An organic silane derivative, such as TMDSO, and pure oxygen as a reactive gas, is used as the gaseous precursor, the ratio between the oxygen flow rate and the gas precursor flow rate being greater than 5, even greater than 15.

According to a fifth embodiment, the procedure is performed to "cool" the surface of the glass. In the case of a magnetron spray tank, the state of freshness of the glass surface is an essential parameter, especially when the layer-coated glass must be tempered afterwards. The glass must not have traces of iridescence. To overcome this problem, a carbon-free SiO2 tank according to the procedure, directly on the glass, is an appropriate solution to cool the surface of the glass and allow the use of old crystals as layer supports, such as Low-E, according to the magnetron technique.

Thus, the deposition of a SiO2 layer avoids these inconveniences, advantageously when its thickness is between 20 and 60 nm. The roughness of SiO2 (Ra) should preferably be less than 5 nm, more preferably less than 2 nm, advantageously less than 0.5 nm.

The procedure is then performed with a power density greater than 5 W / cm2 of plasma for a linear double beam plasma source or greater than 15 kW per meter of plasma for a hollow cathode plasma source, the gas precursor flow rate of an organic silane derivative, such as TMDSO, is less than 200 sccm per linear meter of plasma source, preferably between 50 and 150 sccm per linear meter of plasma source, the deposition rate being less than 200 nm.m / min , preferably less than 150 nm.m / min, in particular less than 100 nm.m / min, the pressure being less than 15 mTorr. An organic silane derivative, such as TMDSO, and pure oxygen as a reactive gas, is used as the gaseous precursor, the ratio between the oxygen flow rate and the gas precursor flow rate being greater than 5, even greater than 15. The source defined in step a) of the PECVD device is placed before the subsequent layer coating system, which can be deposited by magnetron spray or by CVD. This guarantees a percentage of carbon in the SiO2 layer of less than 2%, even less than 0.5% or 0.1%.

The above values of carbon percentages can also be obtained by the addition of an inert gas so that the reactive gas / inert gas ratio is at least 5, advantageously between 5 and 30, in particular having the value of 20. The gas inert is preferably He, Ne, Kr and Ar.

In a variant, the aforementioned carbon percentage values can be obtained by modifying the cathode voltage, which can be done by changing the constituent material of the electrode or by adapting the power generator modules or by modifying the pressure. It is usually passed from a voltage of about 400 V to about 340 V, even 300 V. In another variant, the desired values can be obtained by working in a range of pressures between 5 and 20 mTorr, preferably between 5 and 10 mTorr, being the values of 9-10 mTorr those that give the best results.

PECVD devices that can be used in methods according to the invention will now be described, as examples, while referring to Figures 1 and 2. The different elements of the figures are not shown to scale.

Figure 1: Cross section of a PECVD device comprising a linear double beam plasma source. Figure 2a: cross section of a PECVD device comprising a hollow cathode plasma source. Figure 2b: view of the lower face (facing the substrate) of a hollow cathode plasma source.

In Figure 1, the PECVD source shown is a linear double beam plasma source (10), comprising two cavities (13) in which the discharge takes place, and openings (14) from which it is ejected. Each cavity includes an electrode (12) connected to a power generator (11) that discharges alternative current (AC) or a pulsed Dc. In the plasma source is a series of magnets (15) facing each other and bordering the cavity. The gas injected into each cavity is thus ionized and forms an ion beam, forming what is called a plasma source (16) that is emitted out of the source through an opening (14) in the direction of the substrate to be coated (30) . The arrow indicates the direction of movement of the substrate during the deposit. The total width of the plasma is represented by "w", its total length is measured, in turn, perpendicularly, that is, in the direction of the width of the substrate to be coated.

In Figure 2, the represented PECVD source is a hollow cathode plasma source (20) comprising two cavities (23) that form two electrodes (22) connected to a pulsed AC or DC generator (not shown), in which the discharge takes place, and openings (24) in which the plasma (26) is ejected in the direction of the substrate to be coated (30). The arrow indicates the direction of movement of the substrate during the deposit. The distance between the ends of the plasma in the direction of the width of the substrate to be coated is represented by "L". In this figure, the openings are presented in two rows of outlet holes, but other configurations are possible: for example, a single row of hole or more than two rows of holes, one or several longitudinal grooves.

The invention also relates to films of oxides, nitrides or oxynitrides of metals or semi-conductors selected from the group consisting of SiO2, TiO2, SnO2, ZrO2, A ^ Os, AIN, TiN, ZnO, silicon nitride, TaN, WO3, CrOx and CrN, said components being able to be doped, as well as the alloys of these components, which contain a maximum of 2% atomic residues that come from the precursor, especially selected from the group consisting of H, C, Cl, derivatives of CHx , derivatives of NHx and derivatives of OHx, being x comprised between 1 and 4, obtained by performing the process.

Indeed, the applicant has shown that such films are very advantageously used for the production of layers or layers of layers on substrates, in particular of glass. Thanks to this low content of compounds constituted by the residues that come from the precursors, the layers of these oxides, nitrides or oxynitrides, when deposited on a glass substrate, allow to preserve, even optimize the optical, electrical and structural properties, such as a barrier for the migration of sodium ions, mist control, anti-scratches, anti-reflectants, which allows to "cool" the surfaces of glass substrates, and / or guarantee a homogeneous tempering and without film defect as well deposited

Claims (17)

1. Production process of films of oxides, nitrides or oxynitrides of metals or semi-conductors on a substrate, by means of the PECVD method comprising the steps consisting of: a) be provided with a PECVD device, at low pressure, comprising at least one linear double beam plasma source, which comprises at least two electrodes connected to a pulsed AC or DC generator, for depositing said films on the substratum, b) apply an electric power between the two electrons such that the plasma power density is between 5 and 50 W per cm2 of plasma, and, c) Apply a gaseous precursor of oxides, nitrides or metal or semi-conductive oxynitrides films on the substrate at a flow rate between 100 and 500 sccm per linear meter of the plasma source, and a reactive gas based on oxygen or oxygenated derivatives or nitrogen derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source. 2. Production process of films of oxides, nitrides or oxynitrides of metals or semi-conductors on a substrate, by means of the PECVD method comprising the steps consisting of: a) be provided with a low pressure PECVD device, comprising at least one hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, for depositing said films on the substrate, b) apply an electric power to the plasma source such that the plasma power density is between 15 and 100 kW per meter of plasma, and, c) Apply a gaseous precursor of oxides, nitrides or metal or semi-conductive oxynitrides films on the substrate at a flow rate between 100 and 500 sccm per linear meter of the plasma source, and a reactive gas based on oxygen or oxygenated derivatives or nitrogen derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source. 3. The method according to claim 1, wherein, in step a), the source of the PECVD device has dimensions between 250 mm and 4000 mm in length and between 100 and 800 mm in width, providing a power comprised between 5 kW and 50 kW per linear meter of the plasma source. 4. The method according to one of claims 1 to 3, wherein, in step a), the pressure is between 0.001 and 0.5 Torr. 5. Method according to one of claims 1 to 4, wherein, in step a), the frequencies of the pulsed AC or DC generator are between 5 and 150 kHz. Method according to one of claims 1 to 5, wherein the molar ratio of reactive gas / gaseous precursor is, for films of type M (x) Ox / 2, greater than or equal to (x / 2 - y) / z, where x is the valence of the metal oxide to be obtained, being and the number of oxygen atoms present in the starting precursor and z being the name of oxygen atoms present in the reactive gas. Method according to one of claims 1 to 5, in which the molar ratio of reactive gas / gaseous precursor, for films of type M (x) Nx / 3, is greater than or equal to (x / 3 - y) / z, where x is the valence of the metal nitride to be obtained, being y the number of nitrogen atoms present in the starting precursor and z being the number of nitrogen atoms present in the reactive gas. Method according to one of claims 1 to 7, in which the ratio between the flow rate of the reactive gas and the flow rate of the gaseous precursor is at least 5, advantageously between 5 and 30. 9. The method according to one of claims 1 to 8, wherein the flow rate of the gaseous precursor of oxide, nitride or metal oxynitride films is between 150 and 500 sccm per linear meter of plasma source. 10. Method according to one of claims 1 to 9, wherein the deposition rate is 100 to 400 nm.m / min. 11. Procedure for the production of a glass substrate on which a layer of SiO2 is deposited, in direct contact with the substrate, by means of the PECVD method comprising the steps consisting of: a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons such that the plasma power density is greater than 5 W per cm2 of plasma and less than or equal to 50 W per cm2 of plasma, b.ii) well, in the case of a hollow cathode plasma source, to the plasma source such that the plasma power density is greater than 15 kW per meter of plasma and less than or equal to 100 kW per meter of plasma, c) and, apply a gaseous precursor of an organic silane derivative and pure oxygen on the substrate as a reactive gas at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source, characterized by that: (i) the flow rate of the gaseous precursor of an organic silane derivative is between 100 and 500 sccm per linear meter of the plasma source (ii) the deposition rate is less than 400 nm.m / min, (iii) the pressure of the PECVD device is between 3 and 20 mTorr, (iv) the ratio between the oxygen flow rate and the organic silane derivative flow rate is greater than 5. 12. Procedure for the production of SiO2 layers deposited either directly on a glass substrate, or in stacking with other layers in any position, or as the outermost layer of a stack for the control of mist values in stacks intended for solar applications that incorporate Low-E layers, said mist values being at least 5%, by means of the PECVD method comprising the steps consisting of: a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons, b.ii) or, in the case of a hollow cathode plasma source, to the plasma source, c) and, apply on the substrate a gaseous precursor of an organic silane derivative and an reactive gas based on oxygen or oxygenated derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source, characterized by: (i) the power applied in step b) is such that the plasma power density is between 5 and 10 W per cm2 of plasma for a linear double beam plasma source or between 15 and 20 kW per meter of plasma for a hollow cathode plasma source, (ii) the flow rate of the gaseous precursor of an organic silane derivative is greater than or equal to 100 sccm per linear meter of plasma and less than 400 sccm per linear meter of plasma source, (iii) the ratio between the oxygen flow rate and the gas precursor flow rate is greater than 5, and (iv) the deposition rate is less than 400 nm.m / min. 13. Procedure for the production of layers of SIO2 deposited either directly on a glass substrate, or in stacking with other layers in any position, or as the outermost layer of a stack for the control of mist values in stacks intended for solar applications that incorporate Low-E layers, said mist values being less than 0.5%, by means of the PECVD method comprising the steps consisting of: a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons such that the plasma power density is between 5 and 50 W per cm2 of plasma, b.ii) or, in the case of a hollow cathode plasma source, to the plasma source such that the plasma power density is between 15 and 100 kW per meter of plasma, c) and, apply on the substrate a gaseous precursor of an organic silane derivative and an reactive gas based on oxygen or oxygenated derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source, characterized by: (i) the pressure is greater than 5 mTorr, (ii) the flow rate of the gaseous precursor of an organic silane derivative is greater than or equal to 100 sccm per linear meter of plasma source and less than 400 sccm per linear meter of plasma source, (iii) the ratio between the oxygen flow rate and the gas precursor flow rate is greater than 15, and (iv) the deposition rate is less than 400 nm.m / min. 14. Procedure for the production of selected layers of the group consisting of SiO2, ZrO2 and A ^ O3, deposited either directly on a glass substrate, or as the outermost layer of a stack in order to confer anti-scratch properties to the coated substrate or not, by the PECVD method comprising the steps consisting of: a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons such that the plasma power density is between 10 and 40 W per cm2 of plasma, b.ii) or, in the case of a hollow cathode plasma source, to the plasma source such that the plasma power density is between 20 and 50 kW per meter of plasma, c) and, apply on the substrate a gaseous precursor of metal oxide or semi-conductive films and an reactive gas based on oxygen or oxygenated derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source , characterized by: (i) the pressure is less than 10 mTorr, (ii) the flow rate of the gaseous precursor of metal oxide or semi-conductive films is between 150 and 500 sccm per linear meter of plasma source, (iii) the ratio between the oxygen flow rate and the gas precursor flow rate is greater than 10, and (iv) the deposition rate is less than 400 nm.m / min. 15. Procedure for the production of stacks on a glass substrate that has anti-reflective properties (AR), said stack comprising a succession of layers of high refractive indices and low refractive indices, by the PECVD method comprising the stages that consist of: a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons such that the plasma power density is between 10 and 40 W per cm2 of plasma, b.ii) or, in the case of a hollow cathode plasma source, to the plasma source such that the plasma power density is between 20 and 50 kW per meter of plasma, c) and, apply on the substrate a gaseous precursor of an organic silane derivative and an reactive gas based on oxygen or oxygenated derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source, characterized by: (i) the pressure is less than 20 mTorr, (ii) the flow rate of the gaseous precursor of an organic silane derivative is greater than or equal to 100 sccm per linear meter of plasma and less than 400 sccm per linear meter of plasma source, (iii) the ratio between the oxygen flow rate and the gas precursor flow rate is greater than 5, and (iv) the deposition rate is less than 400 nm.m / min. 16. Process for the production of a transparent SiO2 layer deposited on a glass substrate coated with a Low-E layer, by the PECVD method comprising the steps consisting of: a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons such that the plasma power density is greater than 5 W per cm2 of plasma and less than or equal to 50 W per cm2 of plasma, b.ii) or, in the case of a hollow cathode plasma source, to the plasma source such that the plasma power density is greater than 15 kW per meter of plasma and less than or equal at 100 kW per meter of plasma, c) and, apply on the substrate a gaseous precursor of an organic silane derivative and an reactive gas based on oxygen or oxygenated derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source, characterized by: (i) the pressure is less than 20 mTorr, (ii) the flow rate of the gaseous precursor of an organic silane derivative is greater than or equal to 100 sccm per linear meter of plasma and less than 400 sccm per linear meter of plasma source, (iii) the ratio between the oxygen flow rate and the gas precursor flow rate is greater than 5, and (iv) the deposition rate is less than 200 nm.m / min. 17. Procedure to cool the surface of the glass, a) provide a low-pressure PECVD device, comprising at least: a.i) or a plasma linear double beam source, which comprises at least two electrodes connected to a pulsed AC or DC generator, to. ii) or a hollow cathode plasma source, which comprises at least one electrode connected to a pulsed AC, DC or DC generator, b) apply an electric power b. i) or, in the case of a linear double beam plasma source, between the two electrons such that the plasma power density is greater than 5 W per cm2 of plasma and less than or equal to 50 W per cm2 of plasma, b.ii) or, in the case of a hollow cathode plasma source, to the plasma source such that the plasma power density is greater than 15 kW per meter of plasma and less than or equal at 100 kW per meter of plasma, c) and, apply on the substrate a gaseous precursor of an organic silane derivative and an reactive gas based on oxygen or oxygenated derivatives at a flow rate between 500 and 20,000 sccm per linear meter of the plasma source, characterized by: (i) the flow rate of the gaseous precursor of an organic silane derivative is greater than or equal to 100 sccm per linear meter of plasma and less than 200 sccm per linear meter of plasma source, (ii) the deposition rate is less than 200 nm.m / min, (iii) the pressure is less than 15 mTorr, and (iv) the ratio between the oxygen flow rate and the gas precursor flow rate is greater than 5.